So where would you place these M-301s Nige? I've always considered them to be late to post-war. They're effectively just like the "donut" cushions found in USAAF flight helmets from '43 on. Thanks!
The M301 I think are also just post war they're exactly like Harvard ear cups as you say on the A-11 etc... the key is ,and I'm simply making an educated guess Here Ian is the M301 nomenclature , the reason I say is this...
When I used to collect jet age U.S. Navy flight helmets the inner helmet for the H-4 was basically a nylon AN-H-15 with straps added (almost identical to the late war USN "green Nylon" helmet .
I had two examples, both with the M301 marking on the cups, that's not to say they didn't exist wartime because the green nylon helmets certainly did and were worn in the closing months, but would be very late I think ?
anyone else got concrete info on these ?